Life-long Learning
Becoming a foreign language teacher doesn't happen overnight. It takes time and effort. First of all, one should strive to master the foreign language. And, as you probably know by now, learning a language is a life-long task. There are always new vocabulary words and expressions to learn.
The Advantages of Non-native Speakers as Teachers
There is no doubt that native speakers will always have a special intuition about the language. But a native speaker's intuition doesn't automatically translate into effective language teaching. As Dr. Garza points out, being a non-native teacher brings with it a set of special advantages too, namely the ability to understand the language learner because of personal experience. Moreover, non-native teachers make excellent role models for their students who may not believe that they can ever learn the target language ("I learned this language well so you can too!").
Dr. Garza claims that a professional language teacher must be a life-long learner because languages and cultures constantly change. Have you already noticed changes in your target language—new words, new spellings, new genres? For example, the Internet has given rise to a plethora of neologisms and new language practices? What parts of the target language have you yet to master?